1. Technical Field
The present invention relates to an oscillation circuit.
2. Related Art
Micro-electromechanical systems (MEMS) are one of microstructure formation technologies, and denote, for example, a technology of manufacturing a micron order of fine electronic machine system and products derived therefrom.
In JP-A-2006-224220, there is disclosed a MEMS vibrator having a stationary electrode and a movable electrode, and vibrating the movable electrode due to the electrostatic force generated between the both electrodes.
However, since the MEMS vibrator has a fine structure, the operating characteristics are significantly affected by the variation in the manufacturing process. For example, the MEMS vibrator vibrates at a predetermined frequency due to the drive of the movable electrode, and there is a case in which the shape (the length) of the movable electrode varies due to the variation in the manufacturing process, and thus, stable vibration characteristics (e.g., the frequency accuracy) fail to be obtained. Further, it is extremely difficult to perform trimming on the MEMS vibrator, which is manufactured using the semiconductor integrated circuit manufacturing technology, to thereby tune the frequency with accuracy equivalent to a quartz crystal vibrator.